6.2 REVIEW OF LITERATURE

  INTRODUCTION

       Diabetes mellitus is a complex metabolic disorder characterized by chronic hyperglycaemia due to relative insulin deficiency, resistance or both. In 2017, the International Diabetes Federation estimated that 425 million people (1 in 11 of the global population) had diabetes, and estimates an increase to 693 million by 2045.

      Diabetes is associated with a number of short and long-term complications that reduce quality of life and life expectancy, and are associated with major health costs. These include acute metabolic disturbance, macrovascular disease (leading to an increased prevalence of coronary artery disease, peripheral vascular disease and stroke), and microvascular damage causing retinopathy, nephropathy and neuropathy.

      Diabetes was responsible for approximately 4 million deaths or 10.7% of all deaths in 2017, outnumbering the combined number of global deaths from human immunodeficiency virus (HIV)/acquired immune deficiency syndrome (AIDS), tuberculosis and malaria. A diagnosis of diabetes in a man or woman at the age of 55 years reduces life expectancy by 5 and 6 years, respectively. By contrast, type 2 diabetes diagnosed after the age of 80 years has a limited effect on life expectancy, Heartdisease is the most common cause of death

Accounts for 2/3^rd of all Death with Type-2 DM Aged 65 years or Older. ⁽¹⁾

ETIOLOGY

      Type 2 diabetes Mellitus (T2DM) accounts for around 90Percent of all cases of diabetes. In T2DM, the response to insulin is diminished, and this is defined as insulin resistance. During this state, insulin is ineffective and is initially countered by an increase in insulin production to maintain glucose homeostasis, but over time, insulin production decreases, resulting in T2DM. T2DM is most commonly seen in persons older than 45 years. Still, it is increasingly seen in children, adolescents, and younger adults due to rising levels of obesity, physical inactivity, and energy dense diet.  ⁽²⁾

PATHOPHYSIOLOGY

      Type-2 Diabetes Mellitus Is an insulin-resistance condition with associated beta-cell dysfunction. Initially, there is a compensatory increase in insulin secretion, which maintains glucose levels in the normal range. As the disease progresses, beta cells change, and insulin secretion is unable to maintain glucose homeostasis, producing Hyperglycaemia. Most of the patients with T2DM are obese or have a higher body fat percentage, distributed predominantly in the abdominal region. This adipose tissue itself promotes insulin resistance through various inflammatory mechanisms, including increased FFA release and adipokine dysregulation. Lack of physical activity, prior GDM in those with hypertension or dyslipidaemia also increases the risk of developing T2DM. Evolving data suggest a role for adipokine dysregulation, inflammation, abnormal incretin biology with decreased incretins

Such as glucagon like peptide-1 or incretin resistance, hyperglucagonemia increases renal glucose absorption.  ⁽²⁾

CLINICAL APPROACH TO THE PATIENT WITH DIABETES

·       Presentation

      Presentation may be acute, subacute or asymptomatic, or an individual may present with a complication of diabetes.

·       Acute presentation

      Children and young adults often present with a 2-6-week history of the classic triad of symptoms. Polyuria due to the osmotic diuresis that results when blood glucose levels exceed the renal threshold thirst and polydipsia due to the resulting loss of fluid and electrolytes weight less due to fluid depletion and accelerated breakdown of fat and muticle secondary to insulin deficiency. Ketonuria is often present in young people and may progress to ketoacidosis if these early symptoms are not recognized and treated

·       Subacute presentation

      The clinical onset may be prolonged over several months or years, particularly in older people. Thirst, polyuria and weight loss are usually present, but the individual may complain of other symptoms such as lack of energy, visual blurring (owing to glucose-induced changes in refraction), or pruritus vulvae or balanitis due to Candida infection.

·       Asymptomatic diabetes

        It is estimated that approximately half of people with diabetes are unaware of their condition. This proportion varies across the world. from about a third in high-income countries to three-quarters in some low-income countries. Consequently, up to one-third of diagnoses are made as an incidental finding and several countries have introduced screening programmes to identify those with Asymptomatic undiagnosed diabetes. ⁽¹⁾

INVESTIGATION

1.Blood Glucose estimation

       In Non diabetes, Blood glucose levels are 70-100mg/dl.

   A] Random blood Sugar (RBS) : If Less than140mg Normal , More than 200mg indicate Type-2  Diabetes Mellitus and between 140-200 mg GTT is required

   B] Fasting blood Sugar: Normal Less than 100mg, Diabetes if More than 126mg. If In Between 101-125mg than Prediabetes.

   C] Post prandial Blood sugar: Normal less than 140mg. Diabetes more than 200mg .

2. Two-Hour Oral Glucose Tolerance Test (OGTT)

        In this test, the plasma glucose level is measured before and 2 hours after the ingestion of 75 gm of glucose. DM is diagnosed if the plasma glucose (PG) level in the 2-hour sample is more than 200 mg/dL (11.1 mmol/L). It is also a standard test but is inconvenient and more costly than FPG and has major variability issues. Patients need to consume a diet with at least 150 g per day of carbohydrates for 3 to 5 days and not take any medications that can impact glucose tolerance, such as steroids and thiazide diuretics

3.Glycated Haemoglobin (Hb) A1C

This test gives an average of blood glucose over the last 2 to 3 months. Patients with a Hb A1C greater than 6.5 (48 mmol/mol) are diagnosed as having DM.

4. Urine Examination: Blood sugar level crosses 180mg sugar appear in urine.

5. Self monitoring Device : “Accucheck” Is used. ⁽³⁾

COMPLICATIONS

      Persistent hyperglycaemia in uncontrolled diabetes mellitus can cause several complications, both acute and chronic. Diabetes mellitus is one of the leading causes of cardiovascular disease (CVD), blindness, kidney failure, and amputation of lower limbs. Acute complications include hypoglycaemia, diabetic ketoacidosis, hyperglycaemic hyperosmolar state, and hyperglycaemic diabetic coma. Chronic microvascular complications are nephropathy, neuropathy, and retinopathy, whereas chronic macro vascular complications are coronary artery disease (CAD), peripheral artery disease (PAD), and cerebrovascular disease. ⁽²⁾

GENERAL MANAGEMENT

·       Elimination of the catabolic state and its symptoms

·       Elimination of glycosuria

·       Achievement of pre-prandial and post-prandial glycaemia as indicated by normal HbA1C

·       To prevent or retard the progression of complications associated With diabetes.

·       Prevent metabolic crises like ketoacidosis and hypoglycaemia

·       Maintain normal growth and body weight

·       Encourage self-reliance and self-care

·       Ensure optimum quality of life. ⁽³⁾